1. Technical Field
The present invention relates to a projector capable of projecting an image having undergone trapezoidal correction and an image projection method executed by the projector.
2. Related Art
There has been a known projector that allows reduction in distortion of an obliquely projected image. The projector forms an image in part of an image display area on an image formation panel to correct trapezoidal distortion of a displayed image. In a manual adjustment type projector, in particular, the amount of trapezoidal distortion correction, that is, the amount trapezoidal correction, is saved when the projector is turned off, and the amount of trapezoidal correction is read when the projector is next turned on so that the same trapezoidal correction as that previously performed is performed. In a projector of this type, when a significant amount of trapezoidal correction has been performed before the projector is turned off and then the posture of the projector or any other parameter thereof is greatly changed before the projector is turned on next time, the number of operations for changing the amount of trapezoidal correction to an appropriate value increases when the projector is turned on next time, resulting in a possible cumbersome task. To improve the manual distortion adjustment function of a projector described above, there has been a technique for detecting the angle at which the projector has been installed and trapezoidal correction is automatically performed based on the angle of installation (see JP-A-2003-283963). There has been another technique for automatically correcting trapezoidal distortion by projecting and detecting a detection pattern and concurrently adjusting zooming magnification and other parameters (JP-A-2006-5534 and JP-A-2000-241874).
In the projector described in JP-A-2003-283963, however, the installation angle detector, such as an angle sensor, is required, resulting in a complicated apparatus and an increase in cost.
Similarly, in the projectors described in JP-A-2006-5534 and JP-A-2000-241874, the projection of a detection pattern and the provision of a device for detecting the detection pattern are required, resulting in a complicated apparatus and an increase in cost.